1. Field of the Invention
This invention generally relates to a collection made of pairs of ophthalmic lenses, wherein each lens within said pair comprises at least one antireflection coating having the same perceived chromatic colour of residual reflected light but with a different colour intensity.
This invention also relates to ophthalmic lenses that are provided on their front and rear faces with an antireflection coating which perceived chromatic colour of the residual reflection has a different colour intensity.
2. Description of Related Art
It is usual to apply antireflection coatings to ophthalmic lenses so as to reduce the mean reflection factor.
In this way, the lens wearer's look is made clearer for an observer and the wear comfort is improved for the wearer.
Antireflection coatings most often have a residual colour.
This residual colour is perceived by the person who is facing the lens wearer.
Each ophthalmic lens provided with an antireflection property commercially available under a given trademark has a residual colour which is characteristic of it and the reproducibility of which must be ensured by the manufacturer so as the perceived colour to be substantially the same from one lens to the other, that is to say two lenses resulting from the same industrial process cannot be discriminated between each other and their residual reflections are considered by an observer as being identical.
This residual colour is generally comprised in the green range but other colours such as yellow (gold) or purple are also frequently encountered.
As regards the new lens generations provided with an antireflection property, the general trend does consist in lowering the chroma value so as to make the glass more neutral, that is to say so as to minimize the colour perception.
Recently, it was proposed a range of glasses provided with an antireflection property and having a residual reflection of different colours, notably emerald, amethyst, amber and ruby, to combine with the ophthalmic lens basic hues so as to obtain a cosmetic effect matching-up with the frame.
These colours belong to very varied areas of the spectral range, that is to say having very different hue angles h within the CIE colour-space L*, a*, b*.
This aim does assume the customer to be able to clearly identify the antireflection coating residual colour.
However it has been confirmed that some lenses belonging to this range do present a mean reflection factor Rm≧4% and a luminous reflection factor Rv≧3%, and even ≧4%, which explains that such lenses cannot be truly considered as antireflecting lenses, since a glass provided with an antireflection property must have a luminous reflection factor per face that is 2.5% or less.